North Korea fired at least 100 rockets into the sea Monday, a day after test-launching missiles in violation of UN resolutions. The belligerence from leader Kim Jong-un comes ahead of US-South Korea joint military drills.

Washington — George Washington, go home! That’s the message that North Korean leader Kim Jong-un appears to be sending to the United States and South Korea – by way of a series of missile tests and rocket launches -– as the two Pacific allies prepare for joint military exercises later this week.

The American aircraft carrier George Washington arrived in the South Korean port of Busan Friday in preparation for the annual drills, which begin Wednesday.

North Korea on Monday fired at least 100 artillery shells and rockets into the sea just north of the disputed maritime border with South Korea, according to South Korean military officials.

Monday’s barrage of live-fire weaponry followed a series of missile launches, including Sunday’s firing of two Scud missiles from the North’s western side across the country to the sea on the eastern side. Reports from North Korea announced that Mr. Kim was on hand to observe the missile launches.

North Korea often uses artillery fire or missile tests – the latter prohibited under a series of United Nations Security Council resolutions – to express displeasure at US-South Korean joint exercises or other signs of the close relations between the two allies.

But Kim, the son and grandson of North Korea’s two other Kim leaders, may have extra reason to be mad at the world this year, North Asia analysts say.

A chief one is that Chinese President Xi Jinping pointedly opted to make Seoul – and not Pyongyang – the site of his first visit to the Korean Peninsula as China’s top leader. Kim let his pique show by marking Mr. Xi’s South Korea state visit earlier this month with a round of missile tests.

China has protected North Korea from aggression and diplomatic pressure since its creation after World War II. But it has increasingly bared its mounting exasperation with Pyongyang over its nuclear program and other activities that analysts say Beijing fears could destabilize the region.

In addition, South Korea is increasingly an important commercial partner for China, regional analysts note, while the North and its basket-case economy offer the Chinese little more than exasperation.

Kim’s piques might be of little importance (other than perhaps the fodder they provide for late-night talk-show hosts) except that they can risk destabilizing one of most volatile regions in the world.

In November 2010, North Korea shelled the island of Yeonpyeong, killing four South Koreans and bringing the two Koreas to what many feared was the brink of war. Earlier that same year, a North Korean torpedo sank the South Korean ship the Cheonan. Last year, Kim declared a “state of war” with the South.

Another worrisome aspect of the North’s erratic behavior and Kim’s expressions of fury is that they could be indicators of a power struggle – and thus instability – within the regime in Pyongyang, says Arthur Cyr, political scientist at Carthage College in Kenosha, Wis.

That might sound like something to cheer, given the regime’s abysmal human rights record and the destitute conditions many North Koreans live in. But Mr. Cyr says an insecure regime might also be more prone to the kinds of provocations that have brought the Korean Peninsula close to war in recent years, and could again.